ok so we have been tuning on my ek for about 2 weeks now and we have EVERYTHING perfect on the tune, but at 4500 it has a nasty stutter...but you can push past it and everything is fine...can anyone think of something it could be ...we have check ignition map, ignition timing, cam timing, all sensors are working correctly, did a leak down and everything read below 5%, compression is 190 across the board...

its a turbo h22 tuned with aem ems

 

any ideas?